The 180 E was at one time the top of the line. If I am remembering correctly it took a special type of card in order to get the embroidery onto the machine, most embroidery companies no longer use this. I believe (check with seller) that they also had some sort of free software (think maybe ArtLink) where you could put designs from a CD to your computer and then send to your sewing machine. BSR does not work on this machine
Next top of the line was Artista 200, if that is what the A200 is. I believe that the BSR only works on this machine if it was upgraded ($1,000 upgrade at the time). If I am remembering correctly I believe that this machine takes designs from a stick or through software.
I have in the past had both machines and loved them both, I currently have a 730 (top of the line after the 200) which I have thought about selling to get the 750 (big difference is the new 710, 750, 780 which have the "even feed" feature) but haven't decided yet. I know that personally if I did sell mine I was hoping to get $2,800, with that in mind I don't think I would pay more than $1,800 (if it was converted and has a BSR) for the 200 and probably about $800 for the 180 since it is much older and doesn't have some of the things the 200 has. Also ask about feet as Bernina feet can get quite expensive - I believe the BSR foot is about $800 and the walking foot $150, most of the normal feet are probably in the $40 range.
If either comes with software - check out what kind. I know that for a while ArtLink and aother that I can't remember the name of were free software. The actual sofware is either Designer or Editor I believe and I believe that all have a dongle which you want to treat like gold because there are no free replacements! Also find out what version, I believe the latest is V7 which came out recently
Don't know if that helps any - I hope so.